阴山地区印支期碱性侵入岩岩石地球化学特征  

Petrogeochemical Characteristics of Indosinian Alkaline Intrusions in Yinshan Area

作　　者：阎国翰[1] 谭林坤[1] 许保良[1] 牟保磊[1] 邵宏翔[1] 陈廷礼[1] 童英[1] 任康绪[1] 杨斌[1] 

机构地区：[1]北京大学地质学系,北京100871

出　　处：《岩石矿物学杂志》2001年第3期281-292,共12页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目 (4 930 3170 )

摘　　要：通过系统的矿物学、岩石学、地球化学研究 ,确立了阴山地区印支期碱性岩在空间上分为南北两条近东西走向的岩带。南带以霓辉正长岩为主 ,北带以碱性正长岩为主。南北两带岩体均富集轻稀土元素、大离子亲石元素和高场强元素 ,而Cr、Ni等相容元素含量很低。结合Nd、Sr、Pb同位素特征 ,认为该地区印支期碱性岩源自富集地幔 。Systematic research methods including mineralogy, petrology and geochemistry were used to study the Indosinian alkaline intrusions in Yinshan area. It is concluded that the Indosinian alkaline intrusions in Yinshan area make up two nearly EW_striking rock belts lying in the north and in the south respectively. The southern belt is mainly composed of augite_aegirine syenites, whereas the northern one consists mainly of alkali_syenite. Both belts are enriched in LREE, large_ion lithophile elements and high charge density elements. However, the content of compatible elements such as Cr and Ni are very low. Combined with the isotopic characteristics of Nd, Sr, and Pb, the authors have drawn the conclusion that the Indosinian alkaline intrusions of Yinshan area were generated from the enriched mantal, and during their invasion they were contaminated by crustal materials in different degrees.

关 键 词：印支期 碱性岩 岩石地球化学 富集地幔 板内裂谷环境 阴山地区 锶同位素 稀土元素 钕同位素 

分 类 号：P588.12[天文地球—岩石学] P59[天文地球—地质学]